采用独立分支网络的多源遥感数据自适应融合地物分类

针对现有基于深度学习的地物分类方法大多面向遥感影像,而对点云数据的空间信息利用不足,特别是对点云和影像这种异源特征融合不够充分的问题,提出了一种采用独立分支网络结构的多源遥感数据自适应融合地物分类方法。首先,对配准好的LiDAR点云和遥感影像分别采用三维网络和二维网络提取各模态的空间几何特征和语义特征;其次,在点云空间对影像特征进行交叉模态采样和特征对齐得到基于点的多源特征;最后,采用一种基于注意力机制的非线性自适应特征融合方法实现二、三维语义特征的融合。实验结果表明,本文方法通过网络训练能够实现自适应数据特征的多源遥感数据融合分类,针对ISPRS多源遥感数据集的植被、建筑物和地面三类地物平均分类精度达到85.87%,相较三维点云语义分割的分类精度提高了10.12%。本文提出的独立分支融合网络能够实现二、三维数据的交互学习与深度融合,为遥感多源数据地物分类提供了一种新的思路。     

互注意力融合图像和点云数据的3D目标检测

为了利用图像信息辅助点云数据提高3D目标检测精度,需要解决图像特征空间和点云特征空间自适应对齐融合的问题。本文提出了一种多模态特征自适应融合的3D目标检测深度学习网络。首先,对点云数据体素化,基于体素内的点云特征学习体素特征表示,用3D稀疏卷积神经网络获取点云数据的特征,同时用ResNet神经网络提取图像特征。然后通过引入互注意力模块自适应对齐图像特征和点云特征,得到基于图像特征增强后的点云特征。最后在此特征基础上应用区域提案网络和分类回归多任务学习网络实现3D目标检测。在KITTI 3D目标检测数据集上的实验结果表明:在小汽车的简易、中等、困难三个不同检测难度等级上,平均检测精度分别为88.76%,77.63%和76.14%。该方法能够有效融合图像信息和点云信息,提高3D目标检测的准确率。     

基于云模型的高光谱遥感图像的分类研究

现有的分类方法没有考虑或者没有彻底考虑高光谱遥感图像数据的不确定性,因此提出了一种基于云模型的高光谱遥感图像分类方法。云分类时,首先根据训练样本集,由逆向云发生器生成每类地物的多维云模型,然后利用X条件云发生器计算出各测试像素对每类地物的隶属度,最终采用极大判定法实现对每个测试样本的分类。仿真结果表明,该方法简单、计算量小,可以取得高于传统方法的分类精度,具有很好的发展前景。     

基于区域相似性的高分辨率遥感影像分割

作为蕴含于高分辨率遥感影像中的重要信息,地物目标的光谱特征和纹理结构对其精准分割至关重要。为此,结合高分辨率遥感影像的光谱和纹理信息,提出基于区域相似性的高分辨率遥感影像分割算法。首先,将图像域划分为一系列同质子区域;然后,在区域基础上,结合定义的纹理相似性和光谱相似性,以获取区域相似性;再利用基于区域相似性的分形网络演化算法(FNEA)实现高分辨率遥感影像分割。利用所提出算法,分别对合成纹理图像和高分辨率遥感影像进行分割实验,实验结果表明所提出算法具有一定的可行性及有效性。     

多神经网络图像分割算法

为了提高机器视觉系统的图像分割精度,提出了一种以小波变换为分类特征的多神经网络(Multi-Neural Network,MNN)图像分割算法,该算法包括小波特征提取、MNN区域划分和MNN分类3个阶段。其中,小波特征提取根据小波变换的各层图像扩展得到分类特征;MNN区域划分将初分割边界附近区域分为训练样本区域和待分类区域(待分区域),并用多边形拟合算法将待分区域划分为多个局部待分区域;MNN分类将每个局部待分区域的像素用区域内的神经网络分类器进行分类,确定目标像素和背景像素,将目标像素合并后再进行一定的后处理即可得到分割结果。以轴承表面缺陷检测系统采集的轴承缺陷图像为对象,对MNN算法和阈值分割算法进行了对比试验,结果显示MNN算法的像素数量误差(Pixel Error,PE)相比阈值分割算法降低了75%,分割精度显著提高。     

基于多尺度特征融合的遥感图像场景分类

为了解决遥感图像场景分类中因样本量小而分类精度不高的问题,提出了一种基于多尺度特征融合(MSFF)的分类方法。首先,对遥感图像进行尺度变换,得到同一遥感源图像的多个不同尺度图像。接着,将其分别输入深度卷积神经网络(DCNN)中进行卷积操作。然后,将各卷积层和全连接层提取出的不同尺度特征进行降维和编码/平均池化操作。最后,将各尺度特征进行编码融合并利用多核支持向量机(MKSVM)进行场景分类。在两个公开遥感图像数据集UCM Land-Use和NWPU-RESISC45中进行试验,分类精度最高分别达到98.91%和99.33%。本文方法能够利用不同尺度的图像特征,结合低、中、高层语义表示,使融合特征的可辨识性更高,同时使用多核支持向量机提高了深度网络学习的泛化能力,因此分类效果更好。     

基于CReLU和FPN改进的SSD舰船目标检测

在遥感图像中,舰船目标具有目标尺寸较小、形状细长、多个目标紧密排列、类间相似度高等特点,现有的深度学习目标检测算法对舰船小目标的检测精度不高,易发生错检、漏检情况。为了更有效地利用遥感图像信息,提高小目标检测精度,构建了舰船数据集SDNGV,提出基于串行修正线性单元CReLU和特征金字塔网络(FPN)改进的单射探测器(SSD)舰船目标检测识别方法。首先,在SSD网络的浅层添加CReLU,提升其浅层特征的传递效率;然后,采用FPN从网络的深层到浅层逐级融合SSD中用于检测的多尺度特征图,提升网络的定位精度和分类精度。实验表明,所提目标检测算法具有较好的检测精度,改进方法具有明显的效果,在舰船小目标的检测上有10%的检测精度提升。     

基于分数阶微分的高光谱图像特征提取与分类

针对高光谱遥感图像的特征提取与地物分类,提出一种基于分数阶微分的高光谱图像特征提取方法,设计二维分数阶微分掩模提取高光谱图像的像素空间分数阶微分（SpaFD）特征,并提出一种空谱联合准则用于选取微分掩模阶数。为充分利用高光谱图像的空间特征与光谱特征,将SpaFD特征与原始特征直连融合获得SpaFD-Spe-Spa混合特征,并采用三维卷积神经网络（3DCNN）、先采用主成分分析（PCA）对像素光谱进行降维处理再送入三维卷积神经网络（3DCNNPCA）以及采用混合光谱网络（HybridSN）验证SpaFD-Spe-Spa混合特征的有效性。实验中分别采用3×3,5×5和7×7的分数阶微分掩模进行空间特征提取,4个真实高光谱图像的实验结果表明,所提取的SpaFD特征和SpaFDSpe-Spa特征可有效提升高光谱图像的地物分类精度,且SpaFD-Spe-Spa特征对地物分类准确率的提升更为明显：SpaFD特征相比原始特征在Indian Pines,Botswana,Pavia University和Salinas 4个数据上的分类识别率在最优情况下分别提升了3.87%,1.42%,2.41%和2...     

融合超像素与多模态感知网络的遥感影像车辆检测

针对遥感影像车辆检测中背景干扰、目标密集和目标异质性等因素引起的识别精度下降问题,提出了一种融合超像素与多模态感知网络的遥感影像车辆检测方法。首先,基于混合超像素的区域合并规则,通过超像素二分图融合算法将两种模态的超像素分割结果进行融合,提升了不同模态图像超像素分割结果的准确性;其次,提出一种多模态边缘感知网络的遥感影像车辆检测方法 MEANet (Multi-modal Edge Aware Network),引入OPT-FPN模块（Optimized Feature Pyramid Networks）来增强网络学习多尺度目标特征的能力;最后,通过边缘感知模块聚合超像素和多模态融合模块生成的两组边缘特征,进而生成车辆目标的准确边界。在ISPRS Potsdam和ISPRS Vaihingen遥感影像数据集上进行实验,最终的mF1分数分别为91.05%和85.11%。实验结果表明,本文提出的方法在多模态遥感影像车辆高精度检测中有着较好的检测准确度和较好的应用价值。     

基于改进UNet网络的金丝球焊直径测量研究

提出了一种基于改进UNet网络的金丝球焊焊点精确分割与测量的新方法。改进UNet网络由编码器和解码器两部分构成,其中编码器主要用来提取图像特征,使用在ImageNet数据集上预训练分类网络的卷积模块权重初始化编码器部分,可以在不增加训练数据的情况下,加速网络训练且避免过拟合;解码器主要是结合深层特征和浅层特征以实现精确分割,使用改进的多尺度卷积模块替换原网络中的单尺度卷积模块,使解码器能综合利用不同感受野的特征,进一步提升网络的分割精度。实验结果表明,改进UNet网络与原始UNet网络相比,其测试集分割交并比和F分数分别提升了2.04%和1.58%,且直径测量平均误差从7.734μm降低到1.435μm,满足实际检测需求。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.